Fluid-flow circuit interrupter with arc-assisted piston action

ABSTRACT

A fluid-flow circuit interrupter of the piston type has a serially related pressure-generating arc to mechanically assist the fluid-driving motion of the piston member to offset the arcing pressure generated within the interrupting nozzle by the main current arc disposed therein. The fluid-driving piston is connected by piston rods to the movable contact structure and hence to the operating mechanism. The interrupting device functions to establish a main current arc between the separable main contacts and additionally a pair of serially related arcs, in electrical parallel, on the rear side of the fluid-driving piston to assist the latter in its fluid-driving motion by the pressure generated.

United States Patent [72] Inventors 2,452,477 10/1948 Leeds ZOO/150(E) Russell E. Frink, Pittsburgh, Pa. 2,488,569 11/1949 Strom... 200/150(E) [2]] Applv No. 670,168 2,933,575 4/1960 Baker ZOO/150(6) :gfg fig gfi Primary Examiner-Robert S. Macon a 7 Assignee webfinghouse Elecmc Corporation AttrneysA. T. Stratton, C. L. Mc Hale and W. R. Crout Pittsburgh, Pa. a corporation of Pennsylvania [54] FLUID-FLOW CIRCUIT INTERRUPTER WITH AROASSSTED PISTON ACTION ABSTRA CT: A fluid-flow circult interrupter of the piston type 12 Claims 8 Drawing Figs has a ignzfilygeated pressure-gintiratlng arc to ngzchanicga lly assls e m nvlng motion 0 e piston mem rtoo set [52] U.S. Cl 200/148, h arcing pressure generated within the interrupting nozzle 200/150 by the main current are disposed therein. The fluid-driving [51] Int. Cl ..H0ljh 33/70 piston is connected by piston rods to the movable Contact Fleld Of Search I48 Structure d hence t th p i g mechanism The inter y) 1505: 1506 rupting device functions to establish a main current are 1 Referemsfiwd $5135135$???1172153251233253313211?3: S? UNrTED STATES PATENTS the fluid-driving piston to assist the latter in its fluid-driving 2,420,889 /1947 Leeds 200/ l 50(E) motion by the pressure generated.

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FLUIDJLOW CIRCUIT INTERRUPTER WITH ART ASSISTED PISTON ACTION CROSS REFERENCES TO RELATED APP'LICII'IIONS Applicants are not aware of any related, pending patent ap plications pertinent to the present invention.

BACKGROUND OF THE INVENTION When puffer type circuit interrupters are used to interrupt relatively high fault currents, such as from ,000 amperes up, for example, the arcing pressure generated within the interrupting region is applied to the driving face of the puffer piston, so that excessive energy is required to mechanically drive the fluid-driving piston and force the compressed interrupting gas to flow through the main are for are extinction. This, to a certain extent, has been solved with magnetic assist coils, as described in several patent applications, such as Ser. No. 576,740 filed Sept. 1,19 6. by Russell E. Frink and Wil liam H. Fischer, and .Ser. No. 576,616 filed Sept. 1, 1966, now U.S. Pat No. 3,524,958 by Russell E. Frink both applications assigned to the assignee of the present invention. his a distinct purpose of the present invention to provide another approach 7 to this difiicult problem, which is simpler and less costly to SUMMARY OF THE INVENTION In accordance with a preferred embodiment of the inven tion, there is provided an elongated insulating casing or housing structure, interiorly of which isdisposed a movable fluiddriving piston connected to the movable main contact struc ture, and hence to the operating mechanism. The fluid-driving piston carries a pair of bridgingcontacts,- which in the closed circuit position of the device, electrically engage a pair of sta tionary contacts, which are connected in' the main circuit. During the opening operation, the mechanically provided opening motion ofthe tluid-driving piston and the main movable contact additionally causes the separation of the bridging contacts securedto'and movable with the fluid-driving piston. This causes the establishment of a pair of presume-generating arcs, electrically in parallel, and disposed on the rear side of the fluid-driving'piston, so as to assist the fluid-driving piston by the generation of. pressure on its rear side. This has the advantage of counteracting the excessive arcing back pressure which may be encountered in the stationary interrupting orifice structure adjacent the main current arc.

A general object of the present invention is the provision of i celerated by a pair of electrically parallel arcs disposed on the rear side of the fluid-driving piston so as to mechanically assist the same to overcome the arcing pressure generated at the main movable contacts. 7

Further objects and advantages will readily become ap parent upon reading the following specification, taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates-a perspective view of a three-pole circuit interrupter embodying the principles of the present invention the contact structure being illustrated in the closed-circuit position;

FIG. 2 is a longitudinal vertical sectional view taken through one of the interrupting assemblies of FIG. 1, the contact structure being illustrated in the closed circuit position,

FIG. 3 is a view similar to that of FIG. 2, but illustrating the disposition of the several parts at an intennediate point in the opening operation, illustrating the establishment of the serially related arcs;

FIG. 4 is a detailed sectional view taken substantially along the line IV-IV of FIG. 2;

FIG. 5 is a sectional view taken substantially along the line V-V of FIG. 2;

FIG. 6 is a fragmentary detailed view showing a mounting construction; I

FIG. 7 is a fragmentary longitudinal sectional view taken substantially at right angles to the views of FIGS. 2 and 3, illustrating the piston rod mounting arrangements; and

FIG. 8 is a sectional view taken substantially along the line VIII-VIII of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, and more particularly to FIG. 1 thereof, a reference numeral 1 generally designates a threepole fluid-blast circuit interrupter comprising three spaced pole assembles A, B and C. As will be apparent from FIG. I, each pole assembly includes, generally, an upper end plate 2, a generally upstanding cylindrical housing 3, and a lower end plate and mechanism housing 4. Disposed exteriorly of the mechanism housing 4 is a drive crank 5 afiixed to an operating shaft 6, and a generally horizontally-reciprocally movable insulating operating rod 7 is pivotally secured to the external operating crank 5, as at 8, and is connected to a drive crank 9 through a pivotal connection 10. The three drive cranks 9, only one of which is shown, are affixed and rotatable with an operating drive shaft 11, which is connected to a suitable mechanism 12, which constitutes no of the present invention, and may be of the type set forth in U.S. Pat. No. 3,183,332, issued May 11, 1965, to Russell E. Frink and Paul Olsson, and assigned to the assigneeof the present invention.

It will be apparent from FIG. 1 that a suitable supporting grounded framework 14 is utilized comprising vertical channel members 15 with interbracing structural steel members 16, 16a having horizontally extending insulating support straps 16b secured thereto, which assist in supporting the interrupting assembles assemblies. Additionally, lower insulator supports 17 may be employed extending generally horizontally from a channel support member 16c, the latter being affixed to the vertical support channels 15.

FIGS. 2 and 3 more clearly illustratethe internal construction of each of the interrupting assemblies. With reference to FIG. 2, it will be noted that the insulating casing 3 is preferably a cast resin cylinder, which is cast with an inwardly projecting annular ring 18. Fitted into a recess 18a in the annulus 18 is a Teflon gas guide tube 19 which is retained in this position by the clamp ring 20. A stationary contact tube 22 has a contact foot 23 (FIG..4) brazed to its upper end and is protected by a Teflon tube 24. The stationary contact tube 22 supports an orifice stationary contact 25 and has a portion 220 threaded into a support spider 27. The support spider 27 is attached to the annulus 18 by four bolts 29 (FIG. 6) which also retain the clamp plate 20.

FIG. 2 shows in more detail that the cylinder 3 is closed by the end plate 2 which carries line terminal L1, and by the lever box casting 4 which carries line terminal L2. These members are attached to casing 3 by the bolts 30 which thread into inserts 31 U.S. are cast into the tube 3. Pressure-tight seals are effected by the ring gaskets 32. A moving contact tube 33 is provided which has an internal flow guide 34 movable therewith and slides in the insulating gas guide tube 19. The conducting moving contact tube 33 carries moving contact fingers 35 which engage the stationary contact 25 in the closed position shown in FIG. 2. The moving contact tube 33 makes electrical contact with an end plate portion 4a of the lever box casting 4 through the sliding ball contact arrangement 62, as disclosed in U.S. Pat. No. 3,301,986.

out through a seal in the side of the lever box 4 and rotated by a crank 5 connected to the mechanism as previously explained.

Attached to the yoke 36 by bolts 44 is a pair of insulating piston rods 45. These rods pass through apertures 46 in the annulus 18, and leakage is prevented by the seal rings 47, which are retained by the clamp plate 20. Attached to the opposite ends of the rods 45 by bolts 48 is a movable driving piston 50. The piston 50 slides in the upper cylindrical portion 3a of casing 3 above the annulus 18, and gas leakage is stopped by the piston ring 52.

Referring to FIG. 2, two pairs of movable bridging wedge contacts 54 are attached to the driving piston 50 by bolts 56 sliding in holes 57 through the piston 50. These wedge contacts 54 are biased upwardly by the compression springs 59. In the breaker closed position shown in FIG. 2, two bridging contacts 54 bridge the gap between the contact foot 23, and contact members 61 which are electrically connected to and supported by the upper end plate 2.

In the breaker closed position, the current path is from terminal L1 to plate 2 to contacts 61, to movable wedge contacts 54 to contact foot 23,. to contact tube 22, to moving contact tube33, to sliding ball assembly 62, to lever box 4 to terminal L2. Rotation of shaft 6 in a counterclockwise direction moves links 41 downwardly, which through the yoke 36 moves contact 33, insulating rods 45, and driver putter: piston 50 hausting contact, stationary contact means including a tubular contact cooperable with the aforementioned movable hollow contact to establishamain current aidwitlii'risaid orifice means, piston means including a movable driving piston mechanically connected to themovab le hollow contact, and

said piston means carrying a' mova'ble pressure-generating contact to-establisha serially-related,pressure-generating are adcording to claim '1, wherein the 'ver the stationary hollow gmg contact s to'establish a 7 pair of electrically parallel ai csinseries with the main current arc to assist in the fluid-driving motion of the piston means.

4. The combination according'to claim 1, wherein atleast one piston rod extends through the inwardly extending flange portion of thevcasing to mechanically interconnect the piston means and the hollow movable contact. l

5. A fluid-blast circuit interrupter including means defining hollow contact and carrying a pai r pf ,bridgingcontacts therewith, a movable tubular eontactalways.remainingwithin said orifice member and mechanically operated, by an operatdownwardly. Arcs are drawn between contacts 25 and 34, as

indicated by 63, and between contacts '54 and 61',"which,

quickly assumes the shape shown at 64. The piston50 drives the gas contained in the cylinder 3a, through the main interrupting arc 63, where its temperature is raised to of the order of 10,000 K which results in a tremendous pressure rise. The

likewise raise its pressure in the region 67 thus counterbalancing the pressure in the cylinder 3a. It should also be pointed out that since arcs 64 are in series with are 63, the overall interrupting capacity of the device is increased:

The important feature in this interrupter, which we consider 7 ing mechanism disposed adjacent the other end fsaid insulatingcasing, and the arrangement operating tgprqvide are assisted piston-.movement-during theopening operation to force gas to flow through saidorifice memberand in opposite directions through the separable hollow main contacts.

6. A fluid-blast circuit interrupter including a relatively stationary contact anda cooperable movablercontact separable to establish a main current arc, orifice means for guiding fluid flow-into engagement with said main current arc, means defining'apressure-generating chamber, pressure-generating contact means disposedyithin said pressure-generating chamber to be of the utmost novelty, is' the addition of pressuregenerating arcs 64 to the upper side 67 of'the driving piston have provided an improved low cost piston type circuit interrupter in which the mechanical fluid-driving motion of the piston 50 is assisted by the establishment of one or more serially related arcs 64, which are disposed on the rear side of the fluid-driving piston and assist its downward driving motion.

Although there has been illustrated and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

We claim:

1. A fluid-blast circuit interrupter including a longitudinal insulating casing having an intermediate inwardly extending flange portion, a tubular orifice member secured to said flange portion and accommodating motion of a movable tubular exunder pressure through saidoritice means and into engagement with the main current are :tocffect its extinction, means [positively mechanically connecting, the frnovable piston member to, the movable 'contacnsaid piston member carrying the movable pressure-generating:contacttherewith, the pressure-generating chamber ,being disposed on the rear side of the movable piston member, the pressuie gerierating' arc being established on the rear side of the vablepisto rpember within the pressure-generating chambpf'tothreby assist its fluid-driving motion, K I H "7. The combination accordin g to claim w erein the movable pressure-generating c ta truct'ure c mp pair of. bridging contacts whichestablishin parallel two arcs to assist in the fluid;driving motion of thepiston means.

8. The combination according to claim 6, wherein an insulating longitudinal casing is provided having an inwardly extending supporting flange portion for supporting'said orifice The combination accordingto claim 6, wherein the movable, maincontact doesnotwithdraw outof the orifice means.

lilllt' Tlidcombination according to claim 9, wherein the movable main contact is tubular.

' illl. The combination according to claim 6, wherein both the relatively stationary and the movable main contacts are both tubular. I

12. The combination according to claim 6, wherein the relativeiy stationary main contact is tubular and vents to the rear side of the fluid driving piston. 

1. A fluid-blast circuit interrupter including a longitudinal insulating casing having an intermediate inwardly extending flange portion, a tubular orifice member secured to said flange portion and accommodating motion of a movable tubular exhausting contact, stationary contact means including a tubular contact cooperable with the aforementioned movable hollow contact to establish a main current arc within said orifice means, piston means including a movable driving piston mechanically connected to the movable hollow contact, and said piston means carrying a movable pressure-generating contact to establish a serially related pressure-generating arc disposed on the rear side of the piston means to assist in the fluid-driving motion of the piston means.
 2. The combination according to claim 1, wherein the stationary hollow exhausting contact exhausts to the rear side of the piston means.
 3. The combination according to claim 1, wherein the piston means is annular and slides over the stationary hollow contact, and carries a pair of bridging contacts to establish a pair of electrically parallel arcs in series with the main current arc to assist in the fluid-driving motion of the piston means.
 4. The combination according to claim 1, wherein at least one piston rod extends through the inwardly extending flange portion of the casing to mechanically interconnect the piston means and the hollow movable contact.
 5. A fluid-blast circuit interrupter including means defining an elongated insulating casing having an intermediate inwardly extending supporting flange portion, a tubular orifice member secured to said flange portion, terminal closure means closing one end of said casing and supporting a pair of stationary contacts, a hollow stationary contact supported by said flange portion and carrying a pair of stationary cooperating contacts, an annular piston slidable over said stationary hollow contact and carrying a pair of bridging contacts therewith, a movable tubular contact always remaining within said orifice member and mechanically operated by an operating mechanism disposed adjacent the other end of said insulating casing, and the arrangement operating to provide arc assisted piston movement during the opening operation to force gas to flow through said orifice member and in opposite directions through the separable hollow main contacts.
 6. A fluid blast circuit interrupter including a relatively stationary contact and a cooperable movable contact separable to establish a main current arc, orifice means for guiding fluid flow into engagement with said main current arc, means defining a pressure-generating chamber, pressure-generating contact means disposed within said pressure-generating chamber including a relatively stationary Pressure-generating contact and a relatively movable pressure-generating contact separable to establish a pressure-generating arc within said pressure-generating chamber, means defining an operating cylinder and a movable piston member movable therein to force fluid under pressure through said orifice means and into engagement with the main current arc to effect its extinction, means positively mechanically connecting the movable piston member to the movable contact, said piston member carrying the movable pressure-generating contact therewith, the pressure-generating chamber being disposed on the rear side of the movable piston member, the pressure-generating arc being established on the rear side of the movable piston member within the pressure-generating chamber to thereby assist its fluid-driving motion.
 7. The combination according to claim 6, wherein the movable pressure-generating contact structure comprises a pair of bridging contacts which establish in parallel two arcs to assist in the fluid-driving motion of the piston means.
 8. The combination according to claim 6, wherein an insulating longitudinal casing is provided having an inwardly extending supporting flange portion for supporting said orifice means.
 9. The combination according to claim 6, wherein the movable main contact does not withdraw out of the orifice means.
 10. The combination according to claim 9, wherein the movable main contact is tubular.
 11. The combination according to claim 6, wherein both the relatively stationary and the movable main contacts are both tubular.
 12. The combination according to claim 6, wherein the relatively stationary main contact is tubular and vents to the rear side of the fluid driving piston. 